Ketones ketocarboxylic acid

The nickel hydroxide electrode resembles in its applications and selectivity the chemical oxidant nickel peroxide. The nickel hydroxide electrode is, however, cheaper, easy to use and in scale-up, and produces no second streams/ waste- and by-products [196], Nickelhydroxide electrode has been applied to the oxidation of primary alcohols to acids or aldehydes, of secondary alcohols to ketones, as well as in the selective oxidation of steroid alcohols, cleavage of vicinal diols, in the oxidation of y-ketocarboxylic acids, of primary amines to nitriles, of 2,6-di-tert-butylphenol to 2,2, 6,6 -tetra-rert-butyldiphenoquinone, of 2-(benzylideneamino)-phenols to 2-phenyloxazols, of 1,1-dialkylhydrazines to tetraalkyltetrazenes. For details the reader is referred to Ref. [195]. 

Constitution of the Esters of the (3-Ketocarboxylic Acids and of the P-Diketones.—Ethyl acetoacetate is taken as example. It reacts like a ketone with phenylhydrazine, bisulphite, and other ketone reagents on the other hand it shows an acid reaction, it dissolves in alkalis, and gives the colour reaction with ferric chloride characteristic of ends and also of phenols. From this double behaviour it was formerly concluded that it was either purely ketonic or purely enolic and that the reactions in the other form were to be attributed to a rearrangement caused by the reagents used. The true state of affairs was first disclosed by... 

The butylated /J-ketoester C of Figure 13.26 is not the final synthetic target of the acetoacetic ester synthesis of methyl ketones. In that context, the /J-ketoester C is converted into the corresponding /J-ketocarhoxylic acid via acid-catalyzed hydrolysis (Figure 13.27 for the mechanism, see Figure 6.22). This /i-ketocarboxylic acid is then heated either in the same pot or after isolation to effect decarboxylation. The /f-ketocarboxylic acid decarboxylates via a cyclic six-membered transition state in which three valence electron pairs are shifted at the same time. The reaction product is an enol, which isomerizes immediately to a ketone (to phenyl methyl ketone in the specific example shown). 

Cyclic ketones also can be cleaved by oxidation with KMn04 (Figure 17.33). Under these conditions, 1, -ketocarboxylic acids or 1, -dicarboxylic acids are formed. The mechanism of this reaction is not known in detail. It is known only that KMn04 serves as a three-electron oxidizing reagent and that it is reduced to Mn02. 

The carbonyl group in aldehydes (RCHO) and ketones (RCOR ) is one of the frequently encountered functionalities in the composition of organic compounds. This group has no active hydrogen atoms, excluding the cases of high content of enols for /3-dicarbonyl compounds (/3-diketones, esters of /3-ketocarboxylic acids, etc.) ... 

Ketene, 104, 232 Ketimines, 414 -Ketoacetals, 221 0-Keto allenes, 230, 231 a-Ketocarboxylic acids, 184 1 -Keto-7,7-dimethylnorcarane, 181 a-Keto esters, 237, 245 Ketones, 229, 274 Ketones, resolution, 58, 59... 

Ketocarboxylic acid esters from ketones H —>- COOR... 

Synthesis of ketones from /3-ketocarboxylic acid esters Alkylation of /i-ketocarboxylic acid esters s. 4, 776... 

Ketones from / -ketocarboxylic acid esters COOR —H... 

Triphenylmethyl sodium /J-Ketocarboxylic acids from ketones s. 2, 750 —... 

Ketones from carboxylic acid esters via /5-ketocarboxylic acid esters s. 3, 621... 

Under different reaction conditions, vicinal diol production [70] or C=C double bond oxidative cleavage to carboxylic acids occurs [59, 71], Dialdehydes are produced from cycloolefins, by tungstic acid as catalyst in t-butanol [72], Secondary alcohols yield ketones, while primary alcohols produce aldehydes or carboxylic acids [59, 68-69, 73-74], Different products are obtained from glycols, under different reaction conditions, 1,2-Diols are cleaved to ketocarboxylic acids and dicarboxylic acids [58, 75], or oxidised to a-hydroxy ketones [76], The latter can be obtained directly from the olefins, with lower selectivity [77], Lactones are formed by 1,4-diols and other a,o)-diols [78], Internal alkynes predominantly yield a,p-epoxyketones [79], or 1,2-diketones and carboxylic acids if HgfAcO) is added as the cocatalyst [80], Terminal alkynes yield a-ketoaldehydes and carboxylic acids. 

Hirai, Y., Aida. T, Inoue, S. (1989). Artificial photosynthesis of P-ketocarboxylic acids from carbon dioxide and ketones via enolate complexes of aluminium porphyrin, J. Am. Chem. Soc., Ill 3062. 

Whilst on oxidation of oxoisoatisine (III) the ethylenic linkage in the allyl position to the secondary hydroxyl group is attacked, such reaction is not possible with dihydrooxoisoatisine (IV) instead, the primary hydroxyl group suffers initial oxidation (though slowly) and a monocarboxylic acid (X) results which may be further oxidized to a ketocarboxylic acid (XI), the ketonic group of which is readily detected by its ultraviolet absorption. 

Based on Ochiai s procedure for a-acetoxylation of ketones, Ishihara and coworkers have developed the hypervalent iodine-catalyzed oxylactonization of ketocarboxylic acids to ketolactones [18], Optimized reaction conditions consist of the treatment of a ketocarboxylic acid with iodobenzene (10 mol%), p-toluenesulfonic acid monohydrate (20 mol%) and mCPBA as a stoichiometric oxidant in nitromethane solution Scheme 4.3 shows as a representative example the cyclization of ketocarboxylic acid 4 to ketolactone 5. 

The double unsaturated ketocarboxylic acid [10] was obtained by acylation of oleic acid [la] withcrotonic acid chloride (Scheme 4). Product [10], an allyl vinyl ketone, was formed as a mixture of flie 9- and 10-regioisomers (3). 

Ketones from -ketocarboxylic acid esters CO C COOR CO CH... 

Enollactones from ketocarboxylic acids s. 19, 328 also enolesters from ketones, and dienone-phenol rearrangement s. J. Org. Chem. 31, 324 (1966)... 

Carboxylic from malonic esters s. 22, 84 ketones from -ketocarboxylic acid esters s. H. Hagiwara et al., Bull. Chem. Soc. Japan 48, 3723 (1975)... 

P-ketocarboxylic acid esters 43, 727 ketones, cyclic 44, 928 p-ketothiolic acid esters 43, 727 y-lactones 43,215... 

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